Optic nerve head drusen: a comparative study of 10 MHz and 20 MHz ultrasound probes

The aim of this study was to evaluate and compare 10-MHz and 20-MHz ultrasonography in the assessment of patients with optic nerve head drusen (ONHD). The design of the study was prospective, comparative and cross-sectional. Ultrasonographic examination with a 10 and 20 MHz probe was performed in 45 eyes with suspected ONHD. The 20 MHz probe showed drusen in 43 eyes (95.5 %), while the 10 MHz probe revealed drusen in only 33 eyes (73.3 %, p = 0.0001). The 10 MHz probe showed surface drusen in 10 eyes (22.2 %), while the 20 MHz probe showed surface drusen in 14 eyes (31.1 %) (sensitivity 71.4 %; 95 % CI [47.6-95.1 %]). The 10 MHz probe showed buried drusen in 23 eyes (23.1 %), while the 20 MHz probe showed buried drusen in 29 eyes (64.4 %) (sensitivity 79.3 %; 95 % CI [56.6-86.2 %]). The sensitivity was 76.7 % with 10 MHz probe compared to a 20 MHz as gold standard. The use of 20 MHz probe increased the sensitivity of buried disc drusen by 1.5 times and surface disc drusen by nearly 2 times. Using the 10 MHz probe alone the false negative error rate was 83.3 %. The 20 MHz probe has shown itself to be an excellent method for the diagnosis of ONHD; it is more sensitive and reliable than 10 MHz probe and should be considered in the management of patients with clinical evidence of ONHD.